Method of fashioning a dental prosthesis device and a temporary prosthesis device to put this method into effect

ABSTRACT

A method of making a dental prosthesis device, and an improved device for use as a temporary prosthesis device. A temporary prosthesis device is formed by placing a cap on a tooth-stump, which cap is topped by a soft metal chewing surface. The temporary prosthesis device remains in the patient&#39;&#39;s mouth for several days so that he can perform the action of chewing, so as to shape the soft metal surface. A final prosthesis device provided with a harder metal chewing surface is then fashioned from the model provided by the soft metal chewing surface.

[4 1 Feb.'26, 1974 United States Patent [1 1 Corbineau I i 2 H 2 3 Wk no mo hm ae M we Lo 4 7 w Mn N m a m 4 W w 0 m r P Attorney, Agent, or Firm-Woodhams, Blanchard and Flynn 1 Jean G. Corbineau, 33, rue du Commerce, Paris, France Mar. 23, 1972 Appl. No.: 237,489

[57] ABSTRACT A method of making a dental prosthesis device, and

[22] Filed:

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UNITED STATES PATENTS 3,422,535 Johnson.................................. 32/12 4 Claims, 6 Drawing Figures 1 METH D or FASHIONING A DENTAL PROSTHESIS DEVICE AND A TEMPORARY PROSTHESIS DEVICE TO PUT THIS METHO INTO EFFECT v The present invention relates to a method of making a dental prosthesis device.

A conventional method of making such a device formed for example by a metal crown, consists in fitting on a suitably ground stump of a tooth a metal ring which forms the vestibular, palatine and proximal faces of the tooth, then in taking an impression on the wax on top of the ring,- so that the wax is compressed and I shaped by the opposing tooth.

The final entirely metal crown is then obtained by a wax moulding method.

In order to take the impression in the dentists surgery, the patient is asked to make chewing movements in order to give a functional shape to the wax chewing surface.

However, the length of time that this operation can last is too short and besides thepatient only makes imperfect movements because he does not have the best conditions for regaining the natural movements which are peculiar to himself.

Mechanical articulators have also been proposed to carry out a chewing action in the laboratory after taking several parameters peculiar to the patient, but the movements obtainedin this way are too inexact and m complete. e

IN both cases the result is that this conventional method presents the serious disadvantage. that crowns are obtained with imperfect chewing surfaces which often need to be touched upagain after a more or less prolonged use. e

The object of the present invention is to remedy this difficulty and in order to accomplish this, a method according to the invention is characterized in that it includes fashioning a temporary dental prosthesis device.

provided with one or more crowns each consisting of a cap intended to be put on a stump and topped with a soft metal chewing-surface, putting thetemporary prosthesis device in the mouth of a patient so that he can perform chewing potions for a certain length of time, such as several days, and then forming a'final prosthesis device provided with a harder metal chewing surface obtained from the model provided by the soft metal chewing surface at the end of the said length of time.

Thereby, the soft metal chewing surface of the temporary prosthesis deviceis gradually modelled in the patients mouth during normal use which may stretch over several days and during which the patient easily regains'the natural chewing movements which are peculiar to himself. I

At theend of this period, a perfect impression is obtained on the softmetal of the realchewing points of contact of the tooth and, after a simple shaping with the drill, the tooth can then be given the correct morphological appearance while still respecting the chewing surfaces and from this model a final harder metal chewing surface can be formed by 'any appropriate means.-

The soft metal offers in contrast to wax the obvious advantage of being much more resistant withouthowever causing injury to the patient or damage to the opposing tooth. 4

A final harder metal chewing surface is formed from wax moulding method .in which, after the mould has been formed around the wax model, it is heated causing the wax to flow out, and thus leaving an empty mould.

In such a method the soft metal will be removed like the wax in the above method by flowing out of the mould and leaving room for a harder metal.

This method offers the advantage of being particularly simple and easy to put into effect with the material currently used by dental practioners.

The present invention is also concerned with a, temporary prosthesis device to carryout the method just described, this device being characterized in that it includes one or more crowns each one made up of a cap to be placed on a stump and topped with a soft metal I chewing surface.

In a particular method of execution this apparatus is characterized in that it includes at least two crowns to be placed on a stump and at least one intermediate crown fixed between the two posts thus formed and made up in the same manner as the said crowns, the whole unit forming a temporary bridge.

This temporary bridgecan of course serve as the model to shape a final bridge in harder metal in the same way as before. 1

A crown for a temporary prosthesis device of this invention is made up preferably of a plastic cup topped with an essentially tin chewing surface.

Advantageously the intermediate crown or crowns of the temporary bridge can be fixed together and fitted on. the posts with a self-polymerising resin.

The present invention is also concerned with a method of manufacture of a temporary prosthesis device such as has been described above, characterized in that the cap is formed by injecting the plastic on the tin chewing surface.

This method is particularly advantageous in that it provides a quick and economical way of manufacturing a temporary prosthesis device.

A conventional method and several methods of putting the invention into effect given solely as examples are shown in the accompanying drawings, in which FIG. 1 shows a stage in the formation of a dental crown according to a conventional method, FIGS. 2 and 3 show respectively a temporary crown of the invention in longitudinal cross-section,

FIG; 4 shows in cross-section the crown of FIGS. 2 and 3 mounted on a stump, FIG. 5 shows a temporary bridge of the invention fitted over two stumps, and

FIG. 6 shows a crown mounted thesi plate. I

Referring to the conventional method (FIG. 1) a metal ring 2, fitted over a suitabl} ground tooth-stump 1 forms the vestibular, palatine and proximal faces of the tooth. Then an impression is taken on a block of wax 3 placed on top of the ring 2, the wax being pressed and shaped by the opposing tooth 4. After cutting the on a removable prosoverhanging wax parts 5 a final crown is obtained, for i example in gold, by a wax moulding method.

Very often this crown presents the disadvantage that it is very imperfect'for the reasons given above and must be touched up again after a more or less prolonged use.

A temporary crown according to. the invention (FIGS. 2 and 3) is made up of a relative rigid plastic cap 6 topped by an essentially tin chewing surface 7.

After approximately shaping the chewing surface 7 so that it shows incipient furrows 8 and projections 9 the cap is fitted on a suitably ground stump 10 (FIG. 4)

V preferably covered beforehand by a metal cap (not shown). The cap 6 is fitted on the stump by means of a self-polymerising resin 11 filling the space between the inside face of thecap and the stump.

' During normal use in the patients mouth for a period of about 8 days, the natural chewing action of the jaws gradually works the tin chewing surface 7 and gives it the proper shape.

The temporary crown can then be taken outand, after morphological shaping, it can be used as a model to make a final crown whose chewing surface is made of a harder metal, for example gold.

This final crown can be fashioned by a method such as a conventional wax moulding process in which the tin takes the place of the wax in the conventional 9 Y v W The mould can be heatedto a temperature which not only ensures that the tin will flow but also that the plastic cap 6 is'completely destroyed. In this way an entirely gold final crown can be obtained, it only remaining to fix it permanently to the stump 10.

FIG. S showsa temporary bridge fitted over two stumps 12 also covered beforehand by a metal cap (not shown). On each of the stumps 12 there is fixed a crown made up in the same way as in FIGS. 2 to 4, i.e., provided with a plastic cap 13 overlaid with a preshaped .tin chewing surface 14, as mentioned above. Eachcap l3is also fitted on the corresponding stump 12 by a self-polymerising resin 15.

Between the two posts thus formed there is fixed 56 intermediate crown made up of a plastic-cap 16 overlaid with atin chewing surface 17. The cap is fixed to the two neighbouring caps 13 by a layer of selfpolymerising resin shown at 18. i

The temporary bridge thus obtained is thereby strong enough to easily withstand normal use in the patients mouth for the time required.

At the end of this period the bridge is taken out and the final bridge is shaped, in the same way as described above, the tin'chewing surfaces 14 and 17 forming yet again an excellent model for the final chewing surfaces in a harder metal. v

FIG. 6 shows the fixing of a temporary crown of the present invention to a removable prosthesis plate 19. First of all an artificial stump 20 is formed in selfpolymerising resin, this stump adhering naturally to the plate 19, then on this stump is fitted a temporary crown made up of a'plastic cap 21 topped with a tin chewing 4 stiff ace 22.

It is evident that after several days of chewing in the patients mouth, the tin chewing surface 22 is duly shaped in the same manner as in the previous examples, and that the temporary crown can then be taken out to form the model for the final crown in harder metal.

The temporary crowns of the invention (FIGS. 2 and 3) are manufactured preferably by injecting on the tin chewing surface 7 the plastic which makes up the cap Suitable supports may be provided on the periphery of the chewing surface 7 so as to fix efficiently and simultaneously the chewing surface on the cap.

As the injection temperature of the plastic may be slightly higher than the melting temperature of the tin, a certain proportion of a metal can be added whose melting point is much higher, e.g. silver.

What I claim is:

1. A method of making a dental prosthesis device, comprising the steps of fashioning a temporary prosthesis device having one or more crowns each one constituted by a nonflexible cap to be placed on a toothstump or on a plate and topped by a soft metal chewing surface, positioning the temporary prosthesis device for a period of several days in the patients mouth so that the soft metal chewing surface, and then fashioning a final prosthesis device provided with a harder metal chewing surface from the model provided by the soft metal chewing surface of the temporary prosthesis device at the end of said period.

2. A method according to claim 1, wherein said chewing surface in a harder metal is fashioned on the model of the soft metal chewing surface by a wax moulding process. V TA temporary dental prosthesis device for permitting the fashioning of a permanent dental prosthesis device, said temporary prosthesis device comprising a one-piece cuplike cap defining an opening therein adapted to receive therein a projection, such as a tooth stump, said cap being constructed of a rigid material, and a layer of a soft and readily deformable metal positioned over and fixed to the external closed end wall 'of said cap for defining a soft chewing surface when the prosthesis device is positioned within a patients mouth, said layer of soft metal being of sufficient thickness to permit shaping thereof relative to said end wall prior to mounting of the prosthesis device on the tooth stump and after the prosthesis device has been mounted on the tooth stump due to the natural chewing action of the patients jaws.

4. A prosthesis device according to claim '2, wherein said layer is constructed of tin. 

1. A method of making a dental prosthesis device, comprising the steps of fashioning a temporary prosthesis device having one or more crowns each one constituted by a nonflexible cap to be placed on a tooth-stump or on a plate and topped by a soft metal chewing surface, positioning the temporary prosthesis device for a period of several days in the patient''s mouth so that he can perform the action of chewing so as to shape the soft metal chewing surface, and then fashioning a final prosthesis device provided with a harder metal chewing surface from the model provided by the soft metal chewing surface of the temporary prosthesis device at the end of said period.
 2. A method according to claim 1, wherein said chewing surface of said harder metal is fashioned on the model of the soft metal chewing surface by a wax moulding process.
 3. A temporary dental prosthesis device for permitting the fashioning of a permanent dental prosthesis device, said temporary prosthesis device comprising a one-piece cuplike cap defining an opening therein adapted to receive therein a projection, such as a tooth stump, said cap being constructed of a rigid material, and a layer of a soft and readily deformable metal positioned over and fixed to the external closed end wall of said cap for defining a soft chewing surface when the prosthesis device is positioned within a patient''s mouth, said layer of soft metal being of sufficient thickness to permit shaping thereof relative to said end wall prior to mounting of the prosthesis device on the tooth stump and after the prosthesis device has been mounted on the tooth stump due to the natural chewing action of the patient''s jaws.
 4. A prosthesis device according to claim 2, wherein said layer is constructed of tin. 